Fertilizing a boxwood in a container can help it grow exponentially faster. Furthermore, it adds numerous essential nutrients, allowing the boxwood to absorb more moisture and look much greener. However, adding too much fertilizer or not adding it often enough can have adverse effects on the plant.
To fertilize boxwoods in containers, check and adjust the pH to choose the right fertilizer, then get an all-purpose formula. Aerate the soil before adding one cup of granular fertilizer per foot of boxwood. Water the soil right away. Boxwoods should be fertilized one to two times annually.
Throughout this post, we’ll explain the step-by-step process of fertilizing a boxwood in a container. We’ll also show you a few expert tips to know which fertilizer to choose and how much your plant needs. Enjoy!
1. Correct the Soil’s pH Before Adding the Fertilizer
Always test the soil’s acidity prior to adding fertilizer (source). If you add acidic fertilizer to soil with a low pH, it can cause long-term problems for your boxwood plants. These plants don’t like low-pH soil, so adding fertilizer can actually worsen the issue.
Fortunately, it’s quite easy to adjust the soil’s pH since it’s in a container. If the soil is too alkaline, add a sulfur-based pH reducer. This often comes in powder form to make it easier to spread. Remember, a little bit goes a long way.
If the pH is too low, add a bit of crushed limestone. Lime naturally increases the soil’s pH, so it might become an annual part of your boxwood’s fertilizer routine.
Most fertilizers are slightly acidic. You won’t find too many plants that need an alkaline pH over 7.5, especially not a boxwood. If you add an extremely acidic fertilizer to a boxwood container, the plant will look yellow, dry, and burnt.
2. Choose a Balanced, All-Purpose Fertilizer
Stick to a balanced, all-purpose fertilizer formula for your boxwoods, regardless of if they’re in the garden or in a container. Balanced formulas allow for the best nutrient absorption, but they also prevent your boxwood soil from getting too acidic (which is detrimental, as mentioned above).
The Burpee All-Natural Plant Fertilizer (link to Amazon) is our top choice because it’s balanced, granular, and easy to apply.
One of these four-pound bags covers up to 160 square feet, which is more than enough for several feedings. Seal this bag, and it’ll last your boxwoods multiple years.
Granular fertilizer is usually the best choice for boxwoods because it mixes into the soil quickly. Some granular fertilizers are designed to dissolve in water before being added to the container or garden.
3. Aerate the Soil To Make It Permeable
It’s important to always aerate the soil before adding fertilizer. If you aerate it after fertilizing your plants, the soil won’t be able to absorb nearly as much oxygen and moisture.
The good news is that it’s extremely easy to aerate a boxwood in a container. Follow the steps mentioned below for the best results:
- Use a clean dining fork or a gardening hand fork to poke the soil around the boxwood. If you don’t want to use a fork, you can also use a pencil or a chopstick.
- Stick the tool about two to four inches below the surface every four inches. This will ensure the moisture and fertilizer can get all the way to the roots as quickly as possible.
- Wait for a few minutes to let the soil settle before adding the fertilizer. Many aerated spots will have loose dirt, so you might have to aerate them again.
4. Use One Cup of Granular Fertilizer per Foot of Boxwood
It is generally recommended to use one cup of fertilizer per square foot of boxwood (source). Try the granular fertilizer mentioned above. Make sure the fertilizer is spread evenly throughout the container to prevent it from clumping or missing a few spots. Most granular fertilizers activate immediately.
Another tip is to ensure each of the aerated holes from the previous section has a little bit of fertilizer.
This is where most of the oxygen and moisture will go, so it’s essential that the fertilizer mixes with them. Consider using a mesh screen if the fertilizer scoop doesn’t include a porous membrane.
5. Water the Fertilizer Immediately
Never use any fertilizer if you can’t water it right away. Water right after fertilizing your boxwood plants to help the soil absorb the nutrients. The water also helps prevent the fertilizer from blowing away, evaporating (if it’s liquid), and burning the soil.
Some low-pH fertilizers can cause nitrogen burns if they’re not watered soon enough.
Note: Don’t overwater the fertilizer. A light sprinkle will be enough to activate the granules. Furthermore, try only adding the fertilizer within your current boxwood watering schedule. This ensures your boxwood gets the food it needs without flooding the roots and causing various plant diseases.
6. Create a Boxwood Fertilizer Schedule
A high-quality boxwood fertilizing schedule should consist of the following suggestions:
- Fertilize your boxwoods in their containers one to two times a year.
- If you transplant your boxwood into the garden (out of its container), you can fertilize it between three to four times annually.
- Never let the fertilizer stay on the boxwood leaves because it can cause burn marks.
Choosing the right fertilizer is only half of the equation. It’s crucial to rely on a schedule that ensures your boxwood doesn’t have too much nitrogen in the soil. Annual fertilizing is often enough for most potted boxwood plants, especially if you change the soil just as often.
Boxwoods need fertilizer to grow and have the right amount of nutrients. While most boxwoods will survive without fertilizer, they won’t look as green or grow as quickly as they could.
Fertilizing a boxwood in a container is much easier because you have a small space to work with. Following the suggestions mentioned above will yield optimal results for your boxwoods.